William j



W. 'J. MITCHELL. Paving-Tile;

N .224,93e. Patented Feb. 24, 1880.

N. PETERS. FHOTD-UTHOGRAPHER. WASHINGTON D C side of each of the for UNITED STATES PATENT OFFICE.

'WILLIAM J. MITCHELL, OF SAN FRANCISCO, CALIFORNIA.

PAVING-TILE.

SPECIFICATION forming-part of Letters Patent No. 224,938, dated February 24, 1880. Application filed December 15, 1879.

To all whom it may concern:

Be it known that I, WILLIAM J. MITCHELL, of the city and county of San Francisco, and State of California, have invented an Improved Paving-Tile; and I hereby declare the following to be a full, clear, and exact description thereof.

My invention relates to certain improve ments in tiles and blocks which are employed for paving purposes; and it consists in the formation of a block so that its upper half will project beyond the. lower half upon two adjacent sides, while the lower half projects beyond the upper half upon the two opposite. and adjacent sides, said projecting portions being provided with dovetail depressions and interlocking projections, as hereinafter more fully described and claimed.

By this construction the projecting upper half of each block will rest upon the corre spondin g proj cations of the lower halves of the two blocks lying neXt to it upon these two sides, and each block thus supports two others, and is, in turn, supported by two others.

In combination withithis construction I form a dovetailed locking-groove upon the upper projections of the lower halves, and similar dovetailed projections upon the under sides of the projecting ledges of the upper halves, so that they will tit-into the corresponding grooves of the adjacent blocks or tiles, and thus lock them together and prevent them from becoming separated.

Referring to the accompanying drawings a more complete explanation of my invention, Figure 1 isfa top view of my paving-tile.

I suitable substance.

of solid blocks but ,toform them in molds Fig. 2 is a bottom view.

1 In the formation of my tiles I employ any They may be worked out it will be found preferable from artificial stone.

The blocks may be formed homogeneously, or they mayhave an upper surface of finer material suitablyunited to a body which forms the principal portion of the tile.

A is a tile or paving-block, which is made of such a thickness as will makeit strong enough for the position in which it is to be laid. Upon two adjacent sides projecting ledges B extend outward, these ledges being preferably of half the thickness of the blocks, and they may project far enough to secure a firm support upon the succeeding blocks. Upon the opposite two sides of the block similar projections C extend outward from the lower portion and of half the thickness of it, sothat when a lower one is overlapped by an adjacent upper one the upper surfaces, A, of the blocks will be exactly level and continuous.

Each of the projections C has formed in it centrally a dovetailed depression or groove, D, into which a similarlyformed lug, E, upon the lower face of the projection B may fit.

It will be seen that when the tiles are laid each of theledgesCwill support a corresponding ledge, B, from an adjacent block or tile, and the lugs E will be locked into the depres sion D, so that the blocks will be mutually self-supporting, and will at the same time be bound together and prevented from separatin g. The tiles are thus easily and rapidlylaid, and, being bound together, will not rock oi-become easily displaced when the foundation is imperfect.

It will be usually preferable to lay the tiles with cement, so that when it has set the whole bed will be solid.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

The paving tile or block A, with its ledges B, provided with the dovetailed projections or lugs E, and the ledges C, provided with the corresponding dovetailed depressions D, where by the tiles are supported and locked to prevent lateral separation, 'substantiall y as herein described.

In witness whereof I have hereunto setmy hand.

WILLIAM J. MITCHELL. Witnesses:

GEO. H. STRONG, 'S. H. NoURsE. 

